Police in Texas have arrested a suspect after at least eight people were shot dead at Santa Fe High School, in Santa Fe.

A police officer and students were injured, after a gunman entered the school and started shooting in an art class.

Parent Richard Allen told the Houston television station KTRK he arrived at the school and saw a number of victims taken away in ambulances.

"My son said someone went into the art room and started shooting a lot of the kids," he said.

Joe Giusti, a Galveston County commissioner, said the gunman opened fire inside the school at about 7:45am local time, around the time school was about to start for the day. He said the injured officer worked for the Santa Fe school district as a school resource officer.

The gunman was uninjured, Giusti said.

Raul Reyes, a spokesman for the University of Texas Medical Branch at Galveston, said at least one patient had been taken to the hospital with another taken by helicopter.

In this image taken from video a police officer walks near school buses as law enforcement officers respond to a high school near Houston after an active shooter was reported on campus, Friday, May 18, 2018, in Santa Fe, Texas. The Santa Fe school district issued an alert Friday morning saying Santa Fe High School has been placed on lockdown. (Image: KTRK-TV ABC13 via AP)